The present invention relates to a machine for sealing plastic profiled elements, particularly PVC.
In the state of the art, plastic profiled elements such as PVC or the like, mainly used as frames, are sealed together by melting the respective head surfaces in order to make a surrounding structure which can be fitted to doors, windows or wall frames of same.
In particular, melting is done by heating the portions to be connected by means of suitable heat-sealing plates and then pressing the heated portions the one against the other to facilitate their merger.
Generally, the heated portions are the head ending parts of the profiled elements, suitably cut at 45° to define e.g. a straight corner portion of a respective frame.
This method is implemented by sealing machines equipped with respective retention means of the profiled elements, which are movable in reciprocal approach to bring the heated ending parts to be sealed into contact.
Other machines are furthermore equipped with finishing systems, adapted to remove the sealing seam or bead which forms during the merger of the two profiled elements.
In fact, at the joining line of the two profiled elements (surfaces cut at 45°), the portion of excess melted material comes out and goes to form a bead protruding from the visible surface of the profiled elements which has an ugly appearance as well as nonconformities which can negatively affect the correct installation of the profiled elements themselves.
For this reason, to give the finished frame an appealing appearance and obtain a frame without structural nonconformities, the profiled elements, once sealed, undergo a process of removal of the sealing bead.
Known sealing devices, briefly described above, do however have major drawbacks tied mainly to the formation of the aforementioned sealing bead.
In fact, it must be considered that the sealing area of the plastic profiled elements is not completely uniform and consequently, to make the profiled elements regular, a lot of material is melted with the consequent formation of a large bead, and therefore abundant waste material, which has to be removed.
Furthermore, the finishing operations adapted to remove the bead and clean the sealing area, considerably affect the total frame machining times.
It should be realized in fact that for every frame sealing operation, the profiled elements have to be subsequently machined.
Furthermore, in the case of radial profiled elements the removal of said bead is highly complicated.
To this must be added that the machinery used for the aforementioned finishing operations is cumbersome, complex and particularly expensive.
This involves the need to bear additional costs and processing times, also given the presence of additional cumbersome equipment and tools.
Patent document WO 2013/132406 A1 discloses a method and a device which permit overcoming the aforementioned drawbacks.
The system shown in WO 2013/132406 A1, in fact, is fitted with two movable retention parts on which the profiled elements are mounted and permits sealing them without forming any sealing bead, thanks to a prior milling operation on the areas to seal, adapted to obtain on the profiled elements a containment compartment for the sealing bead, and to the application of containment pressers, which are moved close to the heated profiled elements during sealing and prevent the melted material from coming out of the containment compartment.
An upgraded type of pressing elements is shown in patent document WO 2014/122572 A1. The methods and devices shown on the documents WO 2013/132406 A1 and WO 2014/122572 A1 are also susceptible to further upgrading aimed at obtaining surrounding structures for doors and windows of even better quality.
Such upgrading is aimed at ensuring that, once the head ending parts of the profiled elements have been mutually moved up against one another by means of the movement of the retention means, the profiled elements are interposed between the retention means in a locking configuration such as to prevent the relative rotation of the profiled elements themselves around the relative longitudinal extension axes, or the movement with respect to the reference position in the locking configuration.
It therefore follows that the surrounding structure of the obtained frame is as in conformity as possible and without the structural irregularities particularly evident to the eye.